JP2011240385A - Method and device for manufacturing casting mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for advantageously manufacturing a casting mold having no part of insufficient hardness and having sufficient hardness as a whole.SOLUTION: A primarily-hardened material 74 is formed by supplying heated steam into the inside of the resin-coated sand that is charged in a forming cavity 58, and then primary mold-opening is conducted, in which a gap 78, through which the heated steam flows, is formed between the surface of the primarily-hardened material 74 and a cavity surface 44. Thereafter, the surface of the primarily-hardened material 74 is further hardened by supplying heated steam into the gap 78 and bringing the heated steam into contact with the surface of the primarily-hardened material 74, so that an objective casting mold is manufactured.

Description

  The present invention relates to a mold manufacturing method and a mold manufacturing apparatus, and in particular, an improvement in a method of manufacturing a mold having a predetermined shape by supplying heated steam into a molding cavity filled with resin-coated sand, and its The present invention relates to a mold manufacturing apparatus that can be advantageously employed in such a mold manufacturing method.

  Conventionally, various methods have been adopted in manufacturing a mold made of a sand mold. As one of these mold manufacturing methods, for example, a method disclosed in Japanese Unexamined Patent Publication No. 2000-61583 (Patent Document 1) is known. In this method, a resin-coated sand whose surface is coated with a thermosetting resin binder is filled into a molding cavity, and then heated steam such as water vapor or superheated steam is blown into the molding cavity, and thermosetting is performed. A mold having a predetermined shape is produced by curing the resin binder.

  According to such a method, (a) since the thermosetting resin binder is instantaneously cured by the heated steam blown into the molding cavity, the curing time of the binder and consequently the production time of the target mold (I) It is not necessary to increase the temperature of the forming mold for forming the molding cavity, and the heating cost of the forming mold can be suppressed sufficiently low. (C) Heated steam Is harmless, and a number of merits are also obtained such that generation of harmful gas due to high temperature heating of the thermosetting resin as a binder is advantageously avoided.

  However, when manufacturing a mold using heated steam as described above, the following problems may occur.

  That is, in a conventional mold manufacturing method using heated steam, heated steam is usually blown into a resin-coated sand filled in a molding cavity through a sand blowing port provided in a molding die. Therefore, if the target mold has, for example, a complicated shape having many uneven portions, the portion where the heated steam does not sufficiently spread to the surface layer portion on the cavity surface side of the resin-coated sand in the molding cavity. As a result, there is a risk that such a portion may not be sufficiently cured due to insufficient contact with the heating steam.

  In addition, in order to eliminate such partial curing deficiency of the resin-coated sand in the molding cavity, it is necessary to provide vent holes at various locations on the cavity surface to improve the breathability of heating steam in the molding cavity. Conceivable. However, depending on the shape of the target mold, the structure of the modeling mold, etc., there are places where it is difficult to install vent holes on the cavity surface, and therefore there are cases where vent holes are not provided at appropriate locations on the cavity surface. . In such a case, it is difficult to sufficiently distribute the heated steam to the entire resin-coated sand filled in the molding cavity, which may cause partial curing.

JP 2000-61583 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is to make sure that the entire resin-coated sand filled in the molding cavity is in contact with the heated steam. The present invention provides a method for producing a mold that can be cured sufficiently, and that can stably produce a target mold with sufficient hardness without any insufficient hardness portion. There is. Further, in the present invention, it is an object of the present invention to provide an apparatus that can advantageously manufacture such a mold.

  In the present invention, in order to solve the problems related to the above-described mold manufacturing method, (a) by forming a plurality of molding molds together, formed between the cavity surfaces of the plurality of molding molds Filling the resin-coated sand into the molded cavity, and (b) supplying heated steam to the resin-coated sand filled in the molding cavity to cure the resin-coated sand, Forming a cured product, and (c) after forming the primary cured product, a gap is formed between the surface of the primary cured product and each cavity surface of the plurality of modeling molds so that heating steam can flow. (D) supplying heated steam into the gaps formed by mold opening of the plurality of shaping molds to the position where the plurality of shaping molds are opened, and the primary cured product By contacting the heating steam to the surface, by further curing the primary cured product, the production method of a mold, which comprises a step of molding the mold is for its gist.

  Further, in order to solve the problems related to the mold manufacturing apparatus described above, the present invention provides a plurality of modeling molds that form a molding cavity of a predetermined shape by mold matching, and heating steam in the molding cavity thus formed. A heating steam supply mechanism for supplying the resin, and in the state where the resin-coated sand is filled in the molding cavity, the heating steam is supplied into the molding cavity by the heating steam supply mechanism. An apparatus for producing a mold by forming a cured product of coated sand, wherein (a) the molds of the plurality of modeling molds are combined, and the surface of the cured product and each of the cavities of the plurality of modeling molds The molds of the plurality of modeling molds are divided into two stages: a primary mold opening that forms a gap through which the heated steam can flow and a secondary mold opening that enables the cured product to be released. Open A mold opening / closing mechanism; and (b) in a state in which the plurality of modeling molds are combined by the modeling mold opening / closing mechanism, the heating steam supplied from the heating steam supply mechanism is guided into the molding cavity. One heating steam introduction path, and (c) the primary mold opening of the plurality of modeling molds by the modeling mold opening / closing mechanism is performed, and the gap is formed, and then supplied from the heating steam supply mechanism. Another aspect of the present invention is a mold manufacturing apparatus characterized by including a second heating steam introduction path that guides the heating steam into the gap.

  That is, the mold manufacturing method according to the present invention includes a first heating steam supply operation for supplying heating steam to the inside of the resin-coated sand filled in the molding cavity, and a surface of the primary cured product formed by such operation. The target mold is manufactured by supplying the heating steam into the gap formed between the cavity surface and the second heating steam supply operation for bringing the heating steam into contact with the surface of the primary cured product. It is what I did.

  Therefore, in such a method of the present invention, for example, because the target mold has a complicated shape or the vent hole is not provided at an appropriate position on the cavity surface, the first time In the heating steam supply operation, the surface layer portion of the primary cured product is not sufficiently spread with the heating steam, and even if there is a portion where the contact with the heating steam is insufficient and the curing is insufficient, such a portion is generated. Is sufficiently cured by the contact with the heated steam on the surface of the primary cured product during the second heating steam supply operation.

  Therefore, according to the method for producing a mold according to the present invention as described above, the entire resin-coated sand filled in the molding cavity can be surely brought into contact with heated steam and can be cured more sufficiently. The target mold can be stably manufactured with sufficient hardness without any portion having insufficient hardness.

  And, in the mold manufacturing apparatus according to the present invention, the heating steam from the heating steam supply mechanism can be supplied to the inside of the resin-coated sand filled in the molding cavity through the first heating steam introduction path, Thereby, the primary cured product can be formed. In addition, after forming the primary cured product, the heating steam from the heating steam supply mechanism can be supplied into the gaps formed by the primary mold opening of the plurality of molds by the mold opening / closing mechanism through the second heating steam introduction path. It becomes possible. And thereby, heating steam can be made to contact the surface of primary hardened | cured material, and a primary hardened | cured material can be hardened further. In other words, the production apparatus according to the present invention can be advantageously used in the implementation of a method for producing a mold having the excellent characteristics as described above.

  Therefore, even in such a mold manufacturing apparatus according to the present invention, substantially the same functions and effects as those exhibited in the mold manufacturing method according to the present invention can be enjoyed very effectively. is there.

FIG. 3 is a partial cross-sectional explanatory view showing a main part of a mold manufacturing apparatus according to the present invention, corresponding to the II cross section of FIG. 2. It is II arrow explanatory drawing of FIG. FIG. 5 is a cross-sectional explanatory view showing a state in which the shaping molds mounted on the manufacturing apparatus shown in FIG. 1 are matched, and is a view corresponding to the III-III cross section of FIG. 4. It is IV arrow explanatory drawing of FIG. FIG. 7 is a cross-sectional explanatory view showing a state where the primary mold opening of the shaping mold provided in the manufacturing apparatus shown in FIG. 1 is performed, corresponding to the VV cross section of FIG. 6. It is VI arrow explanatory drawing of FIG. FIG. 2 is an explanatory view showing an example of a process performed when a mold is manufactured using the manufacturing apparatus shown in FIG. 1 according to the method of the present invention, and a molding cavity formed by matching molds The state which filled resin coated sand in the inside is shown. It is explanatory drawing which shows the process example implemented following the process shown by FIG. 7, Comprising: A heating vapor | steam is supplied inside the resin coated sand with which the inside of the shaping | molding cavity was filled, and a primary hardened | cured material is shape | molded. It shows the state. It is explanatory drawing which shows the example of a process implemented following the process shown by FIG. 8, Comprising: After shaping | molding of a primary cured material, the primary mold opening of a shaping | molding type | mold is performed, and between a primary cured material and a cavity surface The heating steam is supplied into the gap formed in Fig. 2 and the mold is formed. It is X arrow explanatory drawing of FIG. It is explanatory drawing which shows the process example implemented following the process shown by FIG. 9, Comprising: The secondary mold opening of the mold for shaping | molding is performed, and the state which released the molded casting_mold | template is shown.

  Hereinafter, in order to clarify the present invention more specifically, the configuration of the present invention will be described in detail with reference to the drawings.

First, in FIG. 1 and FIG. 2, as an embodiment of a mold manufacturing apparatus having a structure according to the present invention, a main part of a mold manufacturing apparatus for manufacturing a predetermined core is shown in a longitudinal sectional form and a planar form. And are shown respectively. As is clear from these drawings, the mold manufacturing apparatus of the present embodiment has a first modeling mold 10 and a second modeling mold 12. The first modeling die 10 and the second modeling die 12 are disposed to face each other in the horizontal direction of FIG. 1 which is the horizontal direction, and can be approached or separated from each other in the facing direction. From the following, unless otherwise specified, the opposing direction of the first modeling die 10 and the second modeling die 12 is referred to as the left-right direction, and the first modeling die 10 and the second modeling die 12 are opposed to each other. The direction that is perpendicular to the direction and is the vertical direction in FIG. 1 is simply referred to as the vertical direction.

  More specifically, the first modeling mold 10 has a first modeling mold main body 14 and a first nested mold 16, and the second modeling mold 12 is a second modeling mold main body. 18 and a second nested mold 20. The first modeling die 10 and the second modeling die 12 have substantially the same structure. Therefore, in the following, only the structure of the first modeling die 10 will be specifically described. Regarding the second modeling die 12, members having the same structure as the members and parts included in the first modeling die 10 Detailed descriptions of the parts are omitted by giving the same reference numerals to FIGS. 1 and 2.

  The first shaping mold main body 14 has a rectangular casing shape as a whole, and has a rectangular frame shape or a rectangular cylindrical peripheral wall portion 24 including four side wall portions 22a, 22b, 22c, and 22d, and the peripheral wall portion. 24 integrally includes a bottom wall portion 26 that closes one of the openings. In addition, the inner space of the first modeling die main body 14 serves as the accommodating portion 27. And such 1st modeling type main body 14 is arrange | positioned in the state which made the accommodating part 27 open toward the right side, and extended the bottom wall part 26 to the up-down direction.

  In such 1st modeling type main body 14, the upper side wall located in the upper side under the arrangement | positioning state of the above 1st modeling type main bodies 14 among the four side wall parts 22a-22d which comprise the surrounding wall part 24. FIG. A die body side sand blowing hole forming groove 28 is formed to extend in the vertical direction at the center of the length direction of the opening side end face of the portion 22a (the direction perpendicular to the paper surface of FIG. 1 and the vertical direction of FIG. 2). Has been. The mold main body side sand blowing hole forming groove 28 has a semicircular cross-sectional shape (cross-sectional shape perpendicular to the extending direction) on the inner peripheral surface thereof. Further, one steam blowing hole forming groove 30 is formed on each end in the length direction of the opening side end face of the side wall portion 22a so as to extend in the vertical direction. Each of the steam injection hole forming grooves 30 has a cross-sectional shape (cross-sectional shape perpendicular to the extending direction) of the inner peripheral surface thereof from a cross-sectional shape of the inner peripheral surface of the mold body side sand injection hole forming groove 28. Is also a large-diameter semicircular shape. Furthermore, a through-hole 32 that penetrates through the end portion in the vertical direction is formed at the end portion on the opening side of the lower side wall portion 22b located on the lower side of the four side wall portions 22a to 22d.

  In addition, on the outer surface of the bottom wall portion 26 of the first modeling die main body 14 (the surface opposite to the side on which the peripheral wall portion 24 is formed), the upper plate-like protrusion 34 and the lower side are lower than the upper end portion and the lower end portion. The side plate-like protrusions 36 are integrally protruded with a sufficient protrusion height. An upper engaging protrusion 38 that protrudes downward at a predetermined height is integrally formed at the protruding tip of the upper plate-shaped protrusion 34, while the protruding tip of the lower plate-shaped protrusion 36 is A lower engagement protrusion 40 that protrudes upward at a predetermined height is integrally formed. The upper and lower engaging protrusions 38 and 40 have a flat plate shape having the same length as the upper and lower side wall portions 22a and 22b, and are separated from the outer surface of the bottom wall portion 26 by a predetermined distance. Opposed.

  A movable plate 41 is disposed between the opposing surfaces of the bottom wall portion 26 of the first modeling die main body 14 and the upper and lower engaging protrusions 38 and 40. The movable plate 41 has a rectangular flat plate shape that is slightly smaller than the bottom wall portion 26 and is movable in the opposing direction of the bottom wall portion 26 and the upper and lower engagement protrusions 38 and 40. Note that the movement of the movable plate 41 toward the bottom wall portion 26 is restricted by the contact of the movable plate 41 with the bottom wall portion 26. Further, the movement of the movable plate 41 toward the upper and lower engagement projections 38 and 40 is regulated by the contact of the movable plate 41 with the upper and lower engagement projections 38 and 40.

  On the other hand, the first nesting die 16 as a whole has a thick rectangular block shape and has a size that can be accommodated in the accommodating portion 27 of the first modeling die main body 14. On one surface in the thickness direction of the first insert mold 16, a cavity forming recess 42 is provided at the center. The cavity forming recess 42 has an inner peripheral surface shape corresponding to the outer surface of a half portion of the core to be shaped, and the inner peripheral surface of the cavity forming recess 42 is a cavity surface 44.

  Further, in the cavity forming recess 42 forming surface of the first insert mold 16, the insert mold side sand blowing hole forming groove 46 is formed in the lateral center of the upper portion of the cavity forming recess 42. It is formed so as to extend straight in the vertical direction. The insert mold side sand blowing hole forming groove 46 has a semicircular inner peripheral surface having the same diameter as the mold body side sand blowing hole forming groove 28 provided in the first modeling mold body 14. Yes. And it opens upward on the upper side surface of the first insert mold 16, and opens downward on the inner peripheral surface of the cavity forming recess 42, that is, the cavity surface 44. On the other hand, a through hole 50 is formed in the horizontal center portion of the lower portion of the first insert mold 16 below the cavity forming recess 42 so as to penetrate the portion in the vertical direction.

  The first telescopic die 16 having such a structure is accommodated in the accommodating portion 27 of the first modeling die main body 14. Further, in the first telescoping mold 16, the cavity forming recess 42 is opened toward the right side through the opening of the housing portion 27 in the housing state in the housing portion 27. The formation surface of the cavity forming recess 42 is exposed to the outside.

  The first nested mold 16 accommodated in the accommodating portion 27 has a plurality (four in this case) with respect to the movable plate 41 arranged on the outer surface side of the bottom wall portion 26 of the first modeling die main body 14. ) Through the connecting pin 52. That is, here, the connecting pins 52 are fixed to the four corners of the movable plate 41 and protrude from the movable plate 41 toward the bottom wall portion 26 of the first modeling die main body 14. The projecting portions of the connecting pins 52 are inserted into the plurality of pin insertion holes 54 provided in the bottom wall portion 26 so as to be slidable in the axial direction, so that the cavity forming recesses in the first telescopic die 16 are formed. It is being fixed to the surface on the opposite side to 42 formation surface.

  On the other hand, the second modeling mold main body 18 and the second telescopic mold 20 included in the second modeling mold 12 are arranged so that the through holes 32 are formed in the second modeling mold main body 18 in the first modeling mold main body 14. The first molding die body 14 and the first telescopic die 16 have the same structure except that the position of the through hole 32 is slightly different. Then, as shown in FIG. 1, such a second shaping mold 12 faces the housing portion 27 of the second shaping mold body 18 and the cavity forming concave portion 42 of the second insert mold 20 toward the left side. Are arranged so as to be opened. Thereby, the 1st modeling mold 10 and the 2nd modeling mold 12 are each the opening end surfaces of the 1st modeling mold main body 14 and the 2nd modeling mold main body 18, or the 1st nested mold 16 and It arrange | positions in the state which each opening end surface of the 2nd nest | insert type | mold 20 mutually opposed.

  Further, under such an arrangement state, the back surface (second side) of the movable plate 41 arranged on the outer surface side of the first modeling die main body 14 (on the side opposite to the side facing the second modeling die main body 18). A ram 56 protruding from a hydraulic cylinder (not shown) is attached to the surface opposite to the side facing the modeling die main body 18. On the other hand, the back surface (opposite side to the first modeling die main body 14) of the movable plate 41 disposed on the outer surface side of the second modeling die main body 18 (opposite side opposite to the first modeling die main body 14). A ram 56 protruding from a hydraulic cylinder (not shown) is also attached to the surface on the opposite side. The rams 56 and 56 are both protruded or retracted in the opposing direction of the first modeling die 10 and the second modeling die 12 based on the operation of the hydraulic cylinder.

  Thus, in the mold manufacturing apparatus of the present embodiment, as shown in FIGS. 1 and 3, the movable plates of the first modeling die 10 and the second modeling die 12 are accompanied by the protrusion operation of the rams 56, 56. 41 and 41 move close to each other and come into contact with the outer surfaces of the first modeling mold main body 14 and the second modeling mold main body 18. Then, as the rams 56 and 56 further project from the state, the movable plates 41 and 41 further move closer to each other, so that the first modeling die body 14 and the second modeling die body 18 respectively. Facing surfaces of each other and the opposing surfaces of the first and second nested molds 16 and 20 come into contact with each other, so that the first modeling mold 10 and the second modeling mold 12 are molds. It is designed to be matched.

  Further, as shown in FIGS. 3 and 4, the molding cavity 58 is provided between the first and second insert molds 16 and 20 in such a mold-matching state. It is formed by the cavity forming recesses 42 and 42 of the second nested molds 16 and 20. The inner surface of the molding cavity 58 is formed by the cavity surfaces 44 and 44 of the first and second telescopic molds 16 and 20, so that the shape of the molding cavity 58 is the target. The shape corresponds to the outer shape of the core.

  Then, under the matching of the first modeling mold 10 and the second modeling mold 12, the mold main body side sand provided on the upper side wall portions 22a of the first modeling mold main body 14 and the second modeling mold main body 18 is provided. A circular mold body side sand blowing hole 60 is formed by the blowing hole forming grooves 28, 28, and the inlets provided in the upper portions of the first and second insert molds 16 and 20 are provided. The child mold-side sand blowing hole forming grooves 46 and 46 form a circular insert mold-side sand blowing hole 62. Further, the mold main body side sand blowing hole 60 and the nested mold side sand blowing hole 62 communicate with each other and are configured as an upper opening that opens the molding cavity 58 upward. Yes. Here, the first heated steam introduction path is constituted by the mold main body side sand blowing holes 60 and the nested mold side sand blowing holes 62.

  Further, under the combination of the first modeling die 10 and the second modeling die 12, steam blowing provided on each upper side wall portion 22a of the first modeling die main body 14 and the second modeling die main body 18 is performed. The corresponding ones of the hole forming grooves 30, 30 form one steam blowing hole 64 on each side of the mold body side sand blowing hole 60. Note that, under the combination of the first modeling die 10 and the second modeling die 12, the lower openings of the two steam injection holes 64, 64 are the first nested die 16 and the second The telescopic mold 20 is closed at each upper end surface.

  Further, under the combination of the first modeling die 10 and the second modeling die 12, the through hole 50 provided in the lower portion of the first nested die 16 is below the first modeling die body 14. The molding cavity 58 communicates with the through holes 32 provided in the side portions, and thereby the molding cavity 58 is opened downward through the through holes 50 and 32. As described above, the formation position of the through hole 32 in the second modeling mold body 18 is different from the formation position of the through hole 32 in the first modeling mold body 14. Therefore, the through hole 50 provided in the lower portion of the second insert mold 20 penetrates the second modeling mold body 18 under the matching of the first modeling mold 10 and the second modeling mold 12. Instead of communicating with the hole 32, the second shaping mold main body 18 is closed by the lower side wall portion 22 b.

  In the mold manufacturing apparatus of this embodiment, as shown in FIGS. 3 and 5, the rams 56, 56 are set to a predetermined amount from the combined state of the first modeling die 10 and the second modeling die 12. The first and second movable molds 41 and 41 are moved to the positions where they are brought into contact with the upper and lower engaging projections 38 and 40 of the first and second shaping mold bodies 14 and 18, respectively. In a state in which the first modeling die main body 14 and the second modeling die main body 18 are matched with each other, only the first nested mold 16 and the second nested mold 20 are slightly opened. A so-called primary mold opening is performed.

  As shown in FIGS. 5 and 6, in such a primary mold open state, the cavity forming recess 42 forming surfaces of the first insert mold 16 and the second insert mold 20 are separated from each other. A gap 66 is formed between them, and the molding cavity 58 is opened to the outside through the gap 66. Further, such a gap 66 communicates with the two steam blowing holes 64 and 64 formed between the first modeling mold body 14 and the second modeling mold body 18. As a result, each of the steam blowing holes 64 and 64 communicates with the molding cavity 58 through the gap 66.

Furthermore, under the primary mold open state, the communication between the through hole 50 formed in the first insert mold 16 and the through hole 32 provided in the first modeling mold body 14 is blocked, while the second mold The through hole 50 formed in the telescopic mold 20 and the through hole 32 provided in the second modeling mold main body 18 communicate with each other. Accordingly, the molding cavity 58 is opened downward through the two through holes 50 and 32 communicating with each other.

  As apparent from FIGS. 1 and 5, the movable plates 41, 41 are brought into contact with the upper and lower engaging protrusions 38, 40 of the first and second shaping mold bodies 14, 18. When the rams 56 and 56 are further retracted from the open state of the primary mold located together, the first modeling mold body 14 and the second modeling are formed together with the first and second telescopic molds 16 and 20. The mold body 18 is moved by the movable plates 41, 41 in directions away from each other. Thus, as will be described later, a so-called secondary mold opening that separates the first modeling mold 10 and the second modeling mold 12 to a position at which the mold modeled in the molding cavity 58 can be released. To be done. As is clear from this, in the present embodiment, the modeling mold opening / closing mechanism includes the movable plates 41, 41, the upper and lower engaging protrusions 38, 40, the rams 56, 56, and a hydraulic cylinder (not shown). It is configured.

  By the way, when the target core is manufactured using the mold manufacturing apparatus of the present embodiment having such a structure, for example, the operation is advanced as follows.

  That is, first, as shown in FIG. 3, the first shaping mold 10 and the second shaping mold 12 are matched to each other, and between the first nesting mold 16 and the second nesting mold 20. The molding cavity 58 is formed in the above.

  Next, as shown in FIG. 7, a known sand supply device 70 in which the resin-coated sand 68 is accommodated is connected to the upper opening of the mold body side sand blowing hole 60. Thereafter, the resin coated sand 68 in the sand supply device 70 is caused to pass through the mold main body side sand injection hole 60 and the nested mold side sand injection hole 62 by the action of the compressed air introduced into the sand supply device 70. The molding cavity 58 is filled.

  At this time, the compressed air blown into the molding cavity 58 together with the resin-coated sand 68 is formed in the first and second telescopic molds 16 and 20, respectively, and a vent hole (not shown) or a first communicating with each other. It is discharged to the outside through the through hole 50 of one nested mold 16 and the through hole 32 of the first modeling mold main body 14. Further, the resin-coated sand 68 used here is easily and quickly cured by contact with heated steam such as steam or superheated steam, for example, a thermosetting resin binder mainly composed of phenol resin or the like. Foundry sand having a surface coated with is used. Specifically, the resin-coated sand 68 described in JP 2000-107835 A, JP 2000-61583 A, JP 2000-79444 A, JP 2000-84641 A, or the like is appropriately selected. To be used.

Next, as shown in FIG. 8, instead of the sand supply device 70, a superheated steam supply pipe 72 is connected to the upper opening of the mold main body side sand blowing hole 60. The superheated steam supply pipe 72 is connected to a superheated steam generator (not shown) at the end opposite to the side connected to the mold body side sand blowing hole 60. Thus, in this operation, the superheated steam generated by the superheated steam generator is transferred from the superheated steam supply pipe 72 through the mold body side sand blowing hole 60 and the nested mold side sand blowing hole 62 into the molding cavity 58. The resin coated sand 68 filled in is blown into the inside. The temperature and vapor pressure of superheated steam blown into the resin-coated sand 68 (inside the molding cavity 58) are not limited in any way, but generally the temperature is about 110 to 180 ° C. The pressure is about 1.5 × 10 ^{−5 to} 10.2 × 10 ⁻⁵ Pa.

  Further, from the superheated steam generator (not shown), two superheated steam supply pipes 73 (only one is shown in FIG. 9) extend in addition to the superheated steam supply pipe 72 connected to the mold body side blowing hole 60. I'm out. Here, the two superheated steam supply pipes 73 are also connected to the upper openings of the two steam blowing holes 64 and 64 at their tip portions. However, as described above, when the first modeling die 10 and the second modeling die 12 are mated, the lower openings of the two steam blowing holes 64 and 64 are closed. Therefore, under the combined state of the first shaping mold 10 and the second shaping mold 12, superheated steam from the superheated steam generator enters the molding cavity 58 through the two steam blowing holes 64 and 64. There is no inspiration.

  Then, as described above, the superheated steam is blown into the resin coated sand 68 only through the mold main body side and the nested mold side sand blowing holes 60 and 62, whereby the resin coated sand 68 is instantaneously heated. Thus, the thermosetting resin binder of the resin-coated sand 68 is quickly cured, so that the primary cured product 74 is molded in a shape corresponding to the molding cavity 58 in the molding cavity 58.

  In addition, although the some convex part 76 is formed in the outer peripheral surface of the primary hardened | cured material 74 shape | molded here, superheated steam may not spread enough in the inside of these convex part 76. FIG. Therefore, in the present embodiment, after the primary cured product 74 is molded, an operation for further curing the surface layer portion of the primary cured product 74 including the plurality of convex portions 76 is performed.

  That is, after forming the primary cured product 74, as shown in FIG. 9, the first nested mold 16 and the second nested mold 16 and the second shaped mold body 18 are combined with each other. The primary mold opening is performed to slightly open the nested mold 20. Thereby, in the molding cavity 58, the formation surface of the convex part 76 of the primary cured product 74 and the cavity surface 44 part constituting the bottom surface of each cavity forming concave part 42 of the first and second telescopic molds 16, 20 A gap 78 extending continuously in the vertical direction is formed.

  This primary mold opening operation is performed when the primary cured product 74 is molded by curing the resin-coated sand 68 in the molding cavity 58. Specifically, for example, 10 to 20 seconds after the first superheated steam supply operation for blowing superheated steam into the resin coated sand 68 is performed. Moreover, although the mold opening amount by the primary mold opening is not particularly limited, the mold opening amount is generally determined by the respective opposing surfaces of the first and second nested molds 16 and 20. The distance is about 1 to 3 mm. When the superheated steam is blown into the resin-coated sand 68, even if the superheated steam is not sufficiently distributed in the convex portion 76 of the primary cured product 74, the convex portion 76 is cured to some extent. Therefore, when the primary mold opening is performed, the surface layer portion of the primary cured product 74 including such convex portions 76 does not collapse.

  Further, as shown in FIG. 10, when the primary mold opening is performed, the two steam blowing holes 64 and 64 are formed so that the first nested mold 16 and the second nested mold 20 face each other. It comes to communicate with the gap 66 formed therebetween. On the other hand, although not shown, the cavity forming recesses 42 and 42 of the first and second telescopic molds 16 and 20 are provided with a slope to form cavities constituting the side surfaces of the cavity forming recesses 42 and 42. The surface 44 portion has an inclined surface configuration that inclines outward from the bottom side of each cavity forming recess 42, 42 toward the opening side. Therefore, in the primary mold open state, between the cavity surface 44 portion constituting the side surface of each cavity forming recess 42, 42 and the outer surface of the primary cured product 74 formed by the cavity surface 44 portion, A fine gap is formed. The fine gap communicates with a gap 66 formed between the opposing surfaces of the first insert mold 16 and the second insert mold 20, and further, the outer surface of the primary cured product 74 and the first insert In addition, the second insert molds 16 and 20 are also communicated with a gap 78 formed between the cavity surface 44 portions constituting the bottom surface of each cavity forming recess 42.

  Therefore, when the primary mold opening is performed, a gap 78 formed so as to continuously extend in the vertical direction is formed between the outer surface on which the convex portion 76 of the primary cured product 74 is formed and the cavity surface 44. A fine gap between the cavity surface 44 portion constituting the side surfaces of the recesses 42 and 42 and the outer surface of the primary cured product 74, and between the opposing surfaces of the first insert mold 16 and the second insert mold 20. The two steam blowing holes 64 and 64 communicate with each other through the gap 66 formed in the first and second holes. That is, the superheated steam flow path that leads from the two steam blowing holes 64 and 64 to the gap 78 between the outer surface where the convex portion 76 of the primary cured product 74 is formed and the cavity surface 44 by the primary mold opening. Will be formed. Here, the second heating steam introduction path is constituted by the superheated steam flow path.

  In this embodiment, the primary mold opening of the first modeling mold 10 and the second modeling mold 12 is performed as described above, and the two steam injection holes 64 and 64 and the gap 78 are communicated with each other. Then, the superheated steam is guided from the superheated steam supply pipe 73 into the two steam blowing holes 64 and 64. Accordingly, the superheated steam is supplied into the gap 78 formed between the outer surface where the convex portion 76 of the primary cured product 74 is formed and the cavity surface 44 through the superheated steam flow path. The superheated steam supplied in the gap 78 is discharged to the outside through the through hole 50 of the second telescopic mold 16 and the through hole 32 of the second shaping mold body 18 that communicate with each other. Become.

  Thus, the superheated steam is brought into contact with the surface of the primary cured product 74 in a state where the primary mold opening is performed. As a result, the surface layer portion of the primary cured product 74, in particular, the surface layer portion of the convex portion 76 that is likely to be insufficiently contacted with the superheated steam when the superheated steam is blown into the resin coated sand 68 is formed. Make sure to cure. At this time, a part of the superheated steam blown from the two steam blowing holes 64 and 64 and the superheated steam blown from the mold body side and the nested mold side sand blowing holes 60 and 62 are primarily cured. It is supplied from the upper surface of the product 74 to the inside of the primary cured product 74. Also by this, the primary cured product 74 is cured better.

  Then, as FIG. 11 shows, the secondary mold opening of the 1st modeling mold 10 and the 2nd modeling mold 12 is performed, and the hardened | cured material obtained by further hardening | curing a primary hardened | cured material (74) is released. Thus, the target core 80 is obtained.

  As described above, in the present embodiment, the operation of bringing the superheated steam into contact with the resin-coated sand 68 filled in the molding cavity 58 is performed under the combined condition of the first and second shaping molds 10 and 12. Under the operation of supplying superheated steam into the sand 68 and the primary mold open state of the first and second shaping molds 10 and 12, superheated steam is applied to the surface of the primary cured product 74 molded in the molding cavity 58. It is carried out by two heating steam supply operations for the contact operation. As a result, even though the surface of the target core 80 is provided with a convex portion 76 that is likely to be insufficient in hardness by the conventional method using the conventional apparatus, such a convex portion 76 is included. It is possible to sufficiently increase the hardness of the entire core 80.

  Therefore, according to this embodiment as described above, the core 80 having a sufficient hardness as a whole and having no portion having insufficient hardness can be manufactured very advantageously and stably.

  In this embodiment, in order to spread the heated steam over the entire resin-coated sand 68 filled in the molding cavity 58, the vent holes are appropriate for the first and second modeling dies 10 and 12. It is not always necessary to provide the correct position. Thereby, the simplification of the structure of the first and second shaping molds 10 and 12 and the entire mold manufacturing apparatus can be advantageously achieved.

  Further, in the present embodiment, during the molding of the target core 80, superheated steam is formed between the cavity surfaces 44 and 44 of the first and second nested molds 16 and 20 and the surface of the primary cured product 74. It is supplied in a gap 78 formed therebetween. Therefore, the temperature of each of the cavity surfaces 44 and 44 is well maintained at a sufficiently high temperature from the start to the end of the molding of the core 80 and further at the start of the manufacture of the core 80 next time. Thus, in order to maintain the surface quality of the core 80 to be manufactured, the first and second insert molds 16 and 20 are specially heated by external heating or the like before starting the manufacture of the core 80. The need can be eliminated. As a result, the core 80 having excellent surface quality can be advantageously manufactured while omitting troublesome operations and extra costs for heating the first and second nested molds 16 and 20. It is.

  The specific configuration of the present invention has been described in detail above. However, this is merely an example, and the present invention is not limited by the above description.

  For example, in the above embodiment, when performing the primary mold opening, the hydraulic cylinder for moving the first telescopic mold 16 (second telescopic mold 20), and when performing the secondary mold opening, A single cylinder is used as a hydraulic cylinder for simultaneously moving one nested mold 16 (second nested mold 20) and the first modeling mold main body 14 (second modeling mold main body 18). It was. However, separate hydraulic cylinders that perform primary mold opening and hydraulic cylinders that perform secondary mold opening may be used independently of each other.

  Further, when performing the primary mold opening and the secondary mold opening, the actuator used to move the first and second nested molds 16 and 20 and the first and second modeling mold main bodies 14 and 18 are: The actuator is not limited to a hydraulic cylinder, and various actuators generally used to perform mold opening can be appropriately employed.

  Furthermore, the specific structure of the mold opening / closing mechanism that performs the primary mold opening and the secondary mold opening is, of course, not limited to the illustrated one.

  Further, in the combined state of the first modeling die 10 and the second modeling die 12, the first overheating (heating) for supplying (introducing) superheated steam into the resin coated sand 68 filled in the molding cavity 58. ) A second superheated (heating) steam introduction path for supplying (introducing) superheated steam into the gap 78 formed between the primary cured product 74 and the cavity surface 44 in the steam-opening path and the primary mold open state. Each structure and its formation position can be changed as appropriate.

  Furthermore, in the embodiment, superheated steam is used as the heating steam, but it is also possible to use steam at a temperature of 100 ° C.

  In addition, in the above-described embodiment, specific examples in which the present invention is applied to a core manufacturing method and a manufacturing apparatus have been shown. However, the present invention includes various mold manufacturing methods other than a core, Of course, it can be advantageously applied to the above.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 1st modeling mold 12 2nd modeling mold 14 1st modeling mold main body 16 1st nesting mold 18 2nd modeling mold main body 20 2nd nesting mold 38 Upper engagement protrusion 40 Lower engagement Protrusion 41 Movable plate 56 Ram 58 Molding cavity 60 Mold body side sand blowing hole 62 Nesting type side sand blowing hole 64 Steam blowing hole 68 Resin coated sand 70 Sand supply device 72, 73 Superheated steam supply pipe 74 Primary cured product 78 Clearance 80 Core

Claims (2)

Filling the resin-coated sand into the molding cavities formed between the cavity surfaces of the plurality of modeling molds by matching the plurality of modeling molds;
A step of curing the resin-coated sand by supplying heated steam into the resin-coated sand filled in the molding cavity, and molding a primary cured product;
After the molding of the primary cured product, the plurality of modeling molds are moved to a position where a gap through which heated steam can flow is formed between the surface of the primary cured product and the cavity surfaces of the plurality of modeling molds. Opening the mold,
A heating steam is supplied into the gap formed by mold opening of the plurality of modeling molds, and the heating steam is brought into contact with the surface of the primary cured product, whereby the primary cured product is further cured, and a mold is obtained. And the process of modeling
The manufacturing method of the casting_mold | template characterized by including. It has a plurality of modeling molds that form a molding cavity of a predetermined shape by mold matching, and a heating steam supply mechanism that supplies heating steam into the molding cavity thus formed, and the resin-coated sand is filled in the molding cavity An apparatus for producing a mold by molding a cured product of the resin-coated sand by supplying heated steam into the molding cavity with the heated steam supply mechanism under the condition where
While performing mold matching of the plurality of modeling molds, a primary mold opening that forms a gap through which the heated steam can flow between the surface of the cured product and the cavity surfaces of the plurality of modeling molds, A modeling mold opening / closing mechanism that performs mold opening of the plurality of modeling molds over two stages of secondary mold opening that enables mold release of the cured product;
In a state where the plurality of modeling molds are combined by the modeling mold opening / closing mechanism, a first heating steam introduction path that guides the heating steam supplied from the heating steam supply mechanism into the molding cavity;
The heating steam supplied from the heating steam supply mechanism is guided into the gap in a state where the primary mold opening of the plurality of shaping molds by the modeling mold opening / closing mechanism is performed and the gap is formed. A second heated steam introduction path;
An apparatus for producing a mold, comprising:

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